Asthma is an inflammatory disease of high prevalence around the world. During development of asthma the presence of oxidative stress has been related to susceptibility and severity of the disease, thus making the use of antioxidant adjuvant therapy with lipoic acid (LA) an interesting treatment option. The objective of the study is to evaluate the efficacy of LA as an adjuvant treatment on functional, antioxidant, inflammatory, quality and control parameters of asthma in human subjects. The trial design is a randomized, double blind, placebo controlled parallel study.